SAED and crystallography

Calibrate before indexing.

Estimate the pattern center, apply a microscope and camera-length calibration, measure reciprocal radii and compare d-spacings with physically permitted reflections.

Neutral demonstration selected-area electron diffraction pattern — Raw demonstration diffraction pattern. No synthetic rings or phase label are embedded in this image.

Pattern to reviewable crystallographic candidates

Automatic indexing is withheld when microscope/camera-length calibration or independent-ring evidence is insufficient.

01 · Input & calibration

Diffraction pattern plus instrument state

Identify microscope, diffraction mode and camera length. Use the matching verified Au standard (30, 40, 50 or 60 cm for JEOL 2100F where applicable); otherwise request a new calibration.

Calibrant: FCC Au reference d-spacings with recorded calibration source
Required review: Direct-beam centre, beam-stop mask, ellipticity and usable reciprocal range

02 · Method & review

Centre, radial profile and independent rings

Estimate and manually correct the centre, calculate azimuthal intensity, select independent peaks and propagate calibration uncertainty into reciprocal spacing and d-spacing.

03 · Scientific results

Indexed reflections with evidence

Measurementsq, d-spacing and uncertainty for each accepted ring

IndexingCandidate hkl, lattice parameter and physically permitted reflections

Fit qualityRing coverage, residual/error and number of independent rings

InterpretationRanked phase candidates, ambiguity and expert acceptance state

04 · Export & provenance

Annotated diffraction evidence

The deliverable distinguishes measured spacings from candidate indexing and records the calibration used.

Publication figuresFull diffraction pattern with centre, accepted rings and indexed annotations plus radial-intensity profile

Crystallographic tableq, d, uncertainty, candidate hkl, residual, lattice parameter and evidence count

Reusable dataAnnotated image, CSV or XLSX reflection table and microscope/camera-length calibration record

Scientific reportPDF and HTML with calibration source, ring evidence, ranked candidates, ambiguity and limitations

A phase candidate is not a confirmed identification without sufficient independent reflections and experimental context.